Lock, restart,logOff and shutdown a computer

 public void PerformOperation(string filename, string arguments)

        {

            using (Process myProcess = new Process())
            {
                myProcess.StartInfo.FileName = Path.Combine(Environment.SystemDirectory, filename);
                myProcess.StartInfo.Arguments = arguments;
                myProcess.StartInfo.UseShellExecute = false;
                myProcess.StartInfo.CreateNoWindow = true;
                myProcess.Start();
               
            }


// lock computer
1) PerformOperation("rundll32.exe", "user32.dll,LockWorkStation");

//Log Off computer
2)PerformOperation("shutdown.exe", "-l");

//Restart computer
3)PerformOperation("shutdown.exe", "-r -t 0");

//Shutdown computer
4)ProcessRequest("shutdown.exe", "-s -t  0");